1. Field of the Invention
The present invention relates to a cooling structure of a heating element and a power conversion device.
2. Description of the Related Art
Patent Document 1 (Japanese Patent Application Publication No. 2013-073964) discloses in paragraph [0001] “The invention relates to a power module that has good heat dissipation and reliability”, and in paragraph [0011] “A heat dissipating portion 307A is provided on one of two surfaces of the flat case that have wide areas and face each other, and a heat dissipating portion 307B is provided on the other surface. The heat dissipating portion 307A and the heat dissipating portion 307B function as heat dissipating walls of the module case 304, and two or more fins 305 are uniformly formed on the outer circumferential surfaces”.
Meanwhile, there is a desire to use a heating element such as a semiconductor module that has been originally designed as a water-cooled one, as an air-cooled one. This is for reasons that adoption of an air-cooled one makes piping for refrigerant and the like unnecessary, thereby having an advantage in maintenance. On the other hand, adoption of the air-cooled one requires attachment of an external cooling fin having a certain degree of size and the like to the heating element. However, a heating element that has been originally designed as a water-cooled one does not assume application of a strong pressing force thereto because the heating element does not assume attachment of an external cooling fin thereto while having small pin fins (fins each projecting in the form of a pin) or the like. Accordingly, when attempting to simply attach an external cooling fin to the heating element by bolting or the like, there is a possibility that the heating element is broken.